A solo hiker shares an expanse of Sand Dunes National Park with no others.

Camera NEX-7

Shutter Speed 1/1600s

ISO 100

Lamar Valley in the northern section of Yellowstone National Park, on a chilly late-December morning shortly after sunrise.

Camera NEX-7

Focal Length 44.2mm

Aperture f/6.3

Shutter Speed 1/3200s

ISO 100

In a remote village on the Rio Negro, northwest of Manaus, Brazil, local boys play marbles on the village sports field. In a couple hours, the village's older males will start their daily adult game of football (soccer) at 5 p.m.

Camera NEX-7

Focal Length 163.1mm

Aperture f/6.3

Shutter Speed 1/320s

ISO 400

Hikers ascend one of the larger dunes at Sand Dunes National Park in southern Colorado, April 2014.

Camera NEX-7

Shutter Speed 1/2500s

ISO 100

Camera NEX-7

Focal Length 65.9mm

Aperture f/5.6

Shutter Speed 1/25s

ISO 100

Baby seal, Galapagos Islands.

Bison in Yellowstone National Park use their snouts during winter to graze on grasses covered by snow.

Camera NEX-7

Focal Length 130.5mm

Aperture f/6.3

Shutter Speed 1/250s

ISO 160

A large thermal pool in the Norris Springs area of Yellowstone National Park gives off steam on a cold December day. The area's many pools and geysers are heated by groundwater above a giant pool of magma 3 miles below.

Camera NEX-7

Focal Length 42.5mm

Aperture f/6.3

Shutter Speed 1/400s

ISO 200

The morning after: An April snowstorm has transformed the usual Sahara-like look of Sand Dunes National Park in southern Colorado.

Camera NEX-7

Shutter Speed 1/500s

ISO 200

Spotted on the way into Seward, Alaska.

Camera NIKON D40

Focal Length 200mm

Aperture f/5.6

Shutter Speed 1/500s

ISO 400

Captured on a beach in the Galapagos Islands.

Camera NIKON D40

Focal Length 55mm

Aperture f/5.6

Shutter Speed 1/1000s

ISO 200

A normally active squirrel monkey sits for a close-up shot. Amazon River area, south of Manaus, Amazonas, Brazil.

Camera NEX-7

Focal Length 200mm

Aperture f/6.3

Shutter Speed 1/250s

ISO 200

Cloud formations along the Rio Negro, Amazonas, Brazil, on a calm-water day.

Camera NEX-7

Focal Length 16mm

Aperture f/7.1

Shutter Speed 1/800s

ISO 100

Rolling into Casper on I-25, a stunning sunset captured by my phone camera.

Camera iPhone 4S

Focal Length 4.28mm

Aperture f/2.4

Shutter Speed 1/736s

ISO 50

In the dead of winter, the sun presents an eerie presence in a scene of geysers' steam and low clouds.